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III-Nitride high-electron mobility transistors (HEMTs) grown on AlN substrates offer significant advantages for high-power, high-frequency applications due to AlN high thermal conductivity and ultra-wide bandgap. However, achieving high-quality thin GaN channel layers on AlN is challenging because of lattice mismatch, which leads to columnar growth. In this work, we present the development of a tw
This article investigates trapping mechanisms in AlGaN/GaN high electron mobility transistors (HEMTs) at cryogenic temperatures (CTs) down to 4.2 K, using pulsed I–V and drain current transient spectroscopy (DCTS) measurements. The results revealed an overall increase of trapping effects at CT. In particular, a substantial increase in current collapse at low temperatures was observed and predomina
This thesis aims to investigate the novel physics around Majorana bound states (MBSs). MBSs are quasiparticle excitations predicted to exist in topological superconductors. Due to the inherent protection they obtain from their topology, they have long been regarded as a promising setup to build a topologically protected quantum computer. Apart from this very practical application, they continue to
The Majorana tetron is a prototypical topological qubit stemming from the ground-state degeneracy of a superconducting island hosting four Majorana modes. This degeneracy manifests as an effective nonlocal spin degree of freedom, the most paradigmatic signature of which is the topological Kondo effect. Degeneracies of states with different fermionic parities also characterize minimal Kitaev chains
The Council of Europe has very recently adopted the Framework Convention on Artificial Intelligence and Human Rights, Democracy and the Rule of Law. This article provides an initial analysis of the CoE AI Convention. It emphasizes the necessity of understanding the CoE AI Convention within the context of its adoption as an international treaty negotiated within the Council of Europe. This context
Oat grain is a traditional human food that is rich in dietary fibre and contributes to improved human health1,2. Interest in the crop has surged in recent years owing to its use as the basis for plant-based milk analogues3. Oat is an allohexaploid with a large, repeat-rich genome that was shaped by subgenome exchanges over evolutionary timescales4. In contrast to many other cereal species, genomic
Feasibility of the promising large intelligent surface (LIS) concept, as well as its scalability, relies on the use of low-cost hardware components, raising concerns about the effects of hardware distortion. We analyze LIS systems with receive-chain (RX-chain) hardware distortion, showing how it may limit performance gains when scaling up these systems. In particular, using the memory-less polynom
A star’s luminosity increases as it evolves along the main sequence (MS), which inevitably results in a higher surface temperature for planets in orbit around the star. Technologically advanced civilizations may tackle this issue by installing artificial structures – starshades – which can reduce the radiation received by the planet. Starshades, if they exist, are potentially detectable with curre
The production, consumption and disposal of plastics in today’s economies simultaneously contribute to climate change and pollution. With expected production growth for plastics, these problems will only exacerbate. To address the plastic crisis, we need a reduction of its production, as well as a fundamental rethinking of our relationship with this material. Reorganising economies to be less reli
This school meals case study forms part of a collection led by the Research Consortium for School Health and Nutrition’s "Good Examples" Community of Practice. The School Meals Case Study of Sweden serves to document how the national school meals programme is organized, funded, and monitored throughout the country. The objectives of this case study include presenting an introduction to the country
Fluorescence microscopy is an effective tool for imaging biological samples, yet captured images often contain noises, including photon shot noise and camera read noise. To analyze biological samples accurately, separating background pixels from signal pixels is crucial. This would ideally be guided by the knowledge of a parameter called the Poisson parameter, 𝜆bg, representing the mean number of
Herein, it is shown that a fully vertical GaN FinFET can reach close to ideal Baliga's figure of merit (BFOM) for thicker drift layers. Devices with drift layers between 1 and 8 (Formula presented.) are simulated using TCAD, and the device geometry is varied to find optimal device performance. For 8 (Formula presented.) drift layers, device operation at the BFOM limit is found with (Formula presen
A complete set of all optical phonon modes predicted by symmetry for bixbyite structure indium oxide is reported here from a combination of far-infrared and infrared spectroscopic ellipsometry, as well as first principles calculations. Dielectric function spectra measured on high quality, marginally electrically conductive melt grown single bulk crystals are obtained on a wavelength-by-wavelength
The development of EU labour and social law has been described as a pendulum in the sense of focus shifting between economic interests, such as competitiveness for industry, and social interests, such as improving working and living conditions. This view is to a large extent based on the presumption that those interests are contrasting and pursuing one of them would necessarily exclude the promoti
Being able to dynamically shape light at the nanoscale is one of the ultimate goals in nano-optics1. Resonant light–matter interaction can be achieved using conventional plasmonics based on metal nanostructures, but their tunability is highly limited due to a fixed permittivity2. Materials with switchable states and methods for dynamic control of light–matter interaction at the nanoscale are there
Transient thermoreflectance (TTR) technique is employed to study the thermal conductivity of β-Ga2O3 and high Al-content AlxGa1-xN semiconductors, which are very promising materials for high-power device applications. The experimental data are analyzed with the Callaway's model taking into account all relevant phonon scattering processes. Our results show that out-of-plane thermal conductivity of
Strain-stress relationships for physical properties are of interest for heteroepitaxial material systems, where strain and stress are inherent due to thermal expansion and lattice mismatch. We report linear perturbation theory strain and stress relationships for optical phonon modes in monoclinic crystals for strain and stress situations which maintain the monoclinic symmetry of the crystal. By us
Presented here is the development and demonstration of a tunable cavity-enhanced terahertz (THz) frequency-domain optical Hall effect (OHE) technique. The cavity consists of at least one fixed and one tunable Fabry-Pérot resonator. The approach is suitable for the enhancement of the optical signatures produced by the OHE in semi-transparent conductive layer structures with plane parallel interface
